Uniflow steam engine

ABSTRACT

A uniflow steam engine including a cylinder having a steam inlet valve in the cylinder head, a piston having a scavenge valve for transfer of steam from the pressure chamber between the piston and cylinder head through the piston to an exhaust region, and a connecting rod having a first operating arm for opening the scavenge valve, and a second operating arm operable by means of a connecting pin extending through the piston to open the steam inlet valve.

United States Patent 1191 [111 3,910,160 Divine 1 Oct. 7, 1975 [5 UNIFLOW STEAM ENGINE 2,671,434 3/1954 Schmiedeskamp 91/273 3,397,619 8/1968 Sturtevamt 91/325 [76] Invent g ifg g gg g' g g- Walnut 3,703,848 11/1972 Brown 91 325 [22] Filed: Nov. 1, 1974 Primary Examir zerPaul E. Maslousky [211 pp No 520 005 Attorney, Agent, or FirmLyon & Lyon 57 ABSTRACT [52] US. Cl. 91/224; 91/243; 91/253;

91/273. 91/325. 91/410 A uniflow steam engine including a cylinder having a 51 m. cm FOIL 21/02- F01 L /16 Steam inlet valve the cylinder head a Piston having 58 Field of Search 91/325 224 243 273 a scavenge valve'for transfer Steam fmm the Pressure chamber between the piston and cylinder head through the piston to an exhaust region, and a con- [56] References Cited necting rod having a first operating arm for opening the scavenge valve, and a second operating arm opera- UNITED STATES PATENTS ble by means of a connecting pin extending through 2 :(PIHS th pi t t p th Steam i l t valve. iesner... 2,219,816 10/1940 Mould 91/325 8 Claims, 5 Drawing Figures I v I US, Patsm 0%. 7,1975

ll UNiELow STEAM ENGINE BACKGROUND OF THE INVENTION Steam engines in which steam is caused to flow in one direction only are known as Uniflow Engines". In this type of engine the cylinder and piston are so arranged that steam enters the cylinder through the cylinder head and exhausts through ports arranged as an annugine has been recognized as a thermodynamically efficient engine, it is a complicated engine having high cost and weight.

Analysis of the uniflow steam engine is found in Gebhardt, Steam Power Plant Engineering, Sixth Edition, at pages 410 and 419 through 424 and also in Practical Engineering, 1948, at pages 167 and 217 through 221.

Typical examples of uniflow steam engines are found in the following patents: US. Pat. No. 361,169; 671,394; 694,547; 734,532; 1,045,630; 2,402,699; 3,397,619; 3,668,974 and 3,703,848, with particular reference to US. Pat. No. 671,394 issued in 1901 which illustrates a poppet valve disposed in the piston and operated by an arm extending from the connecting rod and also a vacuum relief valve operated by pressure differential across the piston.

SUMMARY OF THE INVENTION The present invention is directed to a uniflow steam engine which retains the advantages of the conventional uniflow steam engine while overcoming the disadvantages thereof; the invention being summarized in the following objects:

First to provide a uniflow steam engine, wherein the supply of steam or other pressure fluid, and its exhaust is accomplished in a manner which materially improves the efficiency of the engine in regard to intake and exhaust of the pressure fluid without the use of gear driven cam shafts or the like for operating the flow valves.

Second, to provide a uniflow steam engine which incorporates in the piston a novely arranged intake control means and as well as a novely arranged scavaging means, both being operated by side arms projecting laterally from the connecting rod.

Third, to provide a uniflow steam engine, as indicated in the preceding objects, having a steam inlet valve in the head of each cylinder which is engaged as the piston moves to the top of its stroke by a connecting pin extending through the piston and actuated by an arm projecting laterally from the connecting rod.

Fourth, to provide a uniflow steam engine as indicated in the other objects, in which a scavaging valve in the form of a flexible plate is mounted on the upper surface of the piston and operated by a second connecting pin extending through the piston and actuated by a second arm projecting laterally from the connecting rod.

DESCRIPTION OF THE FIGURES FIG. 1 is a fragmentary sectional view of the uniflow steam engine as the parts appear when the piston approaches the end of its return stroke and the intake valve is open for the entry of steam.

FIG. 2 is a similar fragmentary sectional view showing the parts during the power stroke of the piston at the point in which the intake valve is closed.

FIG. 3 is a similar fragmentary sectional view showing the piston at its completion of the power stroke in which the exhaust ports are open.

FIG, 4 is a similar fragmentary sectional view showing the piston in its mid-region during the return stroke and showing the scavenging valve in its open position.

FIG. 5 is a transverse sectional view taken through 55 of FIG. 3, the portion of the scavenging valve broken away to illustrate the underlying ports.

The uniflow steam engine may comprise one or several cylinders however, a single cylinder designated 1 and associated parts are shown for purposes of illustration. The cylinder 1 is provided with a ring of exhaust channels 2 extending longitudinally and occupying the lower portion of the cylinder. The upper or opposite end of the cylinder 1 is provided with a cylinder head 3 having an inlet valve housing 4. The housing is provided with a bore 5 offset from the axis of the cylinder and intersected by a laterally disposed inlet port 6.

Fitted within the bore 5 is an inlet valve sleeve 7 having a screwthreaded inner end 8 so that the sleeve may be advanced or retracted. The outer end of the sleeve is provided with a plug secured to the sleeve and forming a handle 9 for turning the sleeve. Inwardly of the handle, there is formed a valve chamber 10 having lateral inlet ports 11 communicating with the inlet port 6. The valve chamber communicates with a valve guideway 12 exposed to the interior of the cylinder 1. The juncture between the valve chamber 10 and the guideway 12 forms a valve seat 13.

Fitted within the valve chamber 10 is a valve head 14 which engages the seat 13 and is provided with a polygonal stem 15.

Mounted within the cylinder 1, is a piston 16 having a top wall or head 17 and skirt 18. Formed in the head 17, is a connecting pin bore 1'9 aligned with the valve guideway 12 and a diametrically disposed parallel second connecting pin bore 20. In the region of the connecting pin bore 20, the head 17 of the piston is pierced by a set of scavenging ports 211.

The connecting pin bore 19 receives an inlet control connecting pin 22 and the bore 20 receives a scavenging control connecting pin 23.

Mounted on top of the piston 16 is a flexible valve disk 24 secured in the region of the connecting pin bore 19 by a clamp bar 25. The valve disk 24 overlies the scavenging ports 21 and is engageable by the connecting pin 23.

Joined to the piston 16 by a journal pin 26 is a connecting rod 27, the extended end of which is journaled on a crank shaft bearing 28. The manner in which the piston 16 is joined to the crank shaft bearing 28 forming a part of a crank shaft not otherwise shown, is conventional. Also, the connecting rod 27 is conventional, except that, the connecting rod is provided with diametrically disposed laterally extending arms 29 and 30. As illustrated in the drawings, the upper surfaces of the arms are coplanar with the axis of the journal pin 26,

however; the arms may be angularly positioned or be displaced a short distance above or below the axis of the journal pin.

Operation of the uniflow steam engine is as follows:

Steam is introduced to the inlet ports 6 and 11 for discharge through the valve guideway 12 into the cylinder 1. The length of the connecting pin 19 and the position of the corresponding lateral arm 29 is such that as the piston approaches its upper position as viewed in the drawings, the valve stem is engaged to raise the valve head 14 for the introduction of steam. It should be noted that, during the last portion of the upward or return stroke, the extremity of the arm 29 moves upwardly more rapidly than the piston so that the opening of the inlet valve may occur very close to the upper extremity or completion of the return stroke.

When the piston is forced downwardly by the pressure of the steam to perform its power stroke, the arm 29 tilts upward so as to maintain the inlet valve open for a substantial portion of the down stroke of the piston to insure that ample steam is introduced. The quantity of steam introduced is controlled by vertical adjustment of the inlet valve sleeve 7. If the sleeve is raised, the quantity of steam introduced is reduced, whereas, if the sleeve is lowered, the quantity of steam is increased.

Referring to FIG. 3, as the piston approaches the lower end of its stroke, the exhaust channels 2 are exposed permitting the steam to escape.

Referring to FIG. 4, during a major portion of the upstroke of the piston, the lateral arm 30 is tilted upward raising the connecting pin 23 so as to lift the valve disk 24 and permit steam which has been trapped above the piston to be scavaged through the piston and be exhausted. The exhaust through the scavenging ports 23 as well as the channels 22 is into the crank case of the engine, not shown. The steam may be condensed in the crank case or elsewhere for reuse.

While the term steam is used, it is intended that other fluids may be used, such as liquids which enter a gas phase at acceptable temperatures as well as compressed air or other compressible fluids.

Having fully described my invention it is to be understood that I am not to be limited to the details herein set forth, but that my invention is of the full scope of the appended claims.

I claim:

1. A uniflow steam engine, comprising:

a. a cylinder having a head at one end;

b. a piston reciprocable therein;

c. a steam inlet valve in the cylinder head having an end exposed to the piston;

d. a connecting pin axially slidable in the piston;

e. and a connecting rod and crank shaft drive therefor for reciprocating the piston, the connecting rod including a laterally extending arm engageable with the connecting pin for causing the connecting pin to engage and open the inlet valve during a portion of the movement of the piston from the cylinder head.

2. A uniflow steam engine, as defined in claim 1,

wherein:

a. a scavaging valve is carried by the piston;

b. a second connecting pin is axially slidable in the piston;

c. and the connecting rod includes a second laterally extending arm engageable to open the scavaging valve during a portion of the movement of the piston toward the cylinder head. 3. A uniflow steam engine, as defined in claim 2,

wherein:

a. the piston includes a piston head;

b. the scavaging valve includes at least one perforation adjacent the second connecting pin and a flexible plate overlying the head of the piston and normally closing the perforation and covering said pin, a portion of the plate spaced from said pin and perforation being secured to the piston head whereby on thrust of said pin the plate flexes to expose the perforation.

4. A uniflow steam engine, as defined in claim 1,

wherein:

a. the extended portion of the cylinder is provided with a ring of axially extending exhaust ports uncovered by the piston during final movement from the cylinder head and initial return movement.

5. A uniflow steam engine, as defined in claim 1,

wherein:

a. means is provided in the cylinder head for axially adjusting the inlet valve to change the duration of engagement with its connecting pin and effecting corresponding change in the volume of steam admitted through the inlet valve.

6. A uniflow steam engine, comprising:

a. a cylinder having a head at one end and an extended portion having at least one exhaust port; b. a piston reciprocable in the cylinder between an extended position adjacent the cylinder head and a retracted position exposing the exhaust port;

c. a connecting rod attached to the piston;

d. a crank shaft joined to the connecting rod for causing reciprocation of the piston and angular as well as reciprocal movement of the connecting rod;

e. the connecting rod including oppositely directed arms adjacent its connection to the piston;

f. a scavaging valve operatively connected with one of said arms;

g. and an inlet valve in the cylinder head intermittently connected operatively with the other of said arms.

7. A uniflow steam engine, as defined in claim 6,

wherein:

a. the scavaging valve includes a port penetrating the piston, a flexible plate overlying the port, and an operating means extending between the plate and corresponding arm for lifting the plate from the port.

8. A uniflow steam engine, as defined in claim 6,

wherein:

a. the inlet valve includes an end exposed to the piston and an operating means reciprocable in the piston and dimensioned to connect the inlet valve to the corresponding arm when the piston is in predetermined relation to the cylinder head. 

1. A uniflow steam engine, comprising: a. a cylinder having a head at one end; b. a piston reciprocable therein; c. a steam inlet valve in the cylinder head having an end exposed to the piston; d. a connecting pin axially slidable in the piston; e. and a connecting rod and crank shaft drive therefor for reciprocating the piston, the connecting rod including a laterally extending arm engageable with the connecting pin for causing the connecting pin to engage and open the inlet valve during a portion of the movement of the piston from the cylinder head.
 2. A uniflow steam engine, as defined in claim 1, wherein: a. a scavaging valve is carried by the piston; b. a second connecting pin is axially slidable in the piston; c. and the connecting rod includes a second laterally extending arm engageable to open the scavaging valve during a portion of the movement of the piston toward the cylinder head.
 3. A uniflow steam engine, as defined in claim 2, wherein: a. the piston includes a piston head; b. the scavaging valve includes at least one perforation adjacent the second connecting pin and a flexible plate overlying the head of the piston and normally closing the perforation and covering said pin, a portion of the plate spaced from said pin and perforation being secured to the piston head whereby on thrust of said pin the plate flexes to expose the perforation.
 4. A uniflow steam engine, as defined in claim 1, wherein: a. the extended portion of the cylinder is provided with a ring of axially extending exhaust ports uncovered by the piston during final movement from the cylinder head and initial return movement.
 5. A uniflow steam engine, as defined in claim 1, wherein: a. means is provided in the cylinder head for axially adjusting the inlet valve to change the duration of engagement with its connecting pin and effecting corresponding change in the volume of steam admitted through the inlet valve.
 6. A uniflow steam engine, comprising: a. a cylinder having a head at one end and an extended portion having at least one exhaust port; b. a piston reciprocable in the cylinder between an extended position adjAcent the cylinder head and a retracted position exposing the exhaust port; c. a connecting rod attached to the piston; d. a crank shaft joined to the connecting rod for causing reciprocation of the piston and angular as well as reciprocal movement of the connecting rod; e. the connecting rod including oppositely directed arms adjacent its connection to the piston; f. a scavaging valve operatively connected with one of said arms; g. and an inlet valve in the cylinder head intermittently connected operatively with the other of said arms.
 7. A uniflow steam engine, as defined in claim 6, wherein: a. the scavaging valve includes a port penetrating the piston, a flexible plate overlying the port, and an operating means extending between the plate and corresponding arm for lifting the plate from the port.
 8. A uniflow steam engine, as defined in claim 6, wherein: a. the inlet valve includes an end exposed to the piston and an operating means reciprocable in the piston and dimensioned to connect the inlet valve to the corresponding arm when the piston is in predetermined relation to the cylinder head. 